1. Field of the Invention
The present invention relates to an electronic control device.
Priority is claimed on Japanese Patent Application No. 2011-200758, filed Sep. 14, 2011, the content of which is incorporated herein by reference.
2. Description of Related Art
In the related art, a WDT (Watchdog Timer) is a well-known hardware timer used to monitor the state of a CPU (Central Processing Unit). When the state of the CPU is updated at a given period by the CPU and the signal is not updated within the given period, the WDT detects a timeout and outputs an abnormality. When the WDT is malfunctioning, an abnormality of the CPU may not be detected. Therefore, there is a concern that system reliability may not be ensured.
JP-A-2005-25290 discloses a technology for diagnosing a malfunction of a WDT by determining whether the WDT performs a reset operation on a CPU when a program-running signal (P-RUN signal) supplied from the CPU to the WDT stops.